Here's my brief "non-music programmer impression":
To me, "classic hits" feels like oldies opened up to the newer "oldies". It seems to the natural progression for stations like WMJI, which have to stem off demo erosion at the older end on the FM dial.
"Oldies", in 2008, feels to me like the station is trying to hold the line on going too "new". And then, of course, there's Scott Shannon-style so-called "real oldies", which feels to me like the station is shouting "we have the *real* oldies you won't find on those 'classic hits' stations'".
Examples: I don't expect to hear 50's stuff on a "classic hits" station. I don't expect to hear 80's stuff on an "oldies" station. But that's just my thought, and in practice, it varies.
Two prime examples of all this...the ABC/Citadel 24 hour satellite network once known as "Pure Gold", later known as "Oldies Radio", is now officially using the name "Classic Hits Radio" on the air. I haven't gone over their music playlist with a magnifying glass, but it seems to me they've gone with newer "oldies" as a natural format progression.
And just down the road from OMW World HQ, over in Warren, Beacon Broadcasting's WANR/1570 has also adopted the official, on-air name of "Classic Hits 1570". Last time I was over there, I heard them play, and no, I'm not making this up, the very recent Santana hit "Smooth". Does Santana get a "new song from classic hits act" pass?
I haven't been within WANR's signal range overnights, or their web stream hasn't worked, so I don't know if they are indeed running ABC/Citadel's "Classic Hits Radio" in off hours. I got the idea that they just run automated music after Johnny Rogers leaves the building at 6-ish. But if they are running the ABC format (and Beacon has a history running those formats), that might explain the on-air name change.